Variable stroke plunger pump



v 1366- 196-9 v. M. JEMISON 3,486,455

VARIABLE STROKE PLUNGER PUMP Filed May 9, 1968 MM m Mi .w #23 HA Mm V wNM United States Patent Office Patented Dec. 30, 1969 3,486,455 VARIABLE STROKE PLUNGER PUMl Volney M. Jemison, Phoenix, Ariz., assignor to Mini ector Corp., Phoenix, Ariz., a corporation of Arizona Filed May 9, 1968, Ser. No. 727,822 Int. Cl. F04b 49/00, 19/22, 7/06 US. Cl. 10338 1 Claim ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION (1) The field of this invention lies in fluid pressure pumps, particularly in variable stroke plunger pumps of the reciprocating plunger or piston type.

(2) Heretofore reciprocating plunger pumps of the rotary piston type required complex mechanisms to adjust the stroke and delivery of the pump.

Further, these mechanisms were exterior of the pump plunger and usually required special lubrication and maintenance independent of the pump plunger and its cylinder.

Also, in former spiral groove rotary reciprocating plunger pumps, difliculty has been experienced in providing a smooth variation and quiet operation and accuracy in the stroke of the pump at low delivery volumes.

SUMMARY OF THE INVENTION One of the objects of this invention is to provide a variable stroke plunger pump having a sprial actuating groove with angularly moving mechanism to accurately change the position of the element operating in the spiral groove so as to vary the stroke and provide quiet delivery of the pump at any stroke setting.

A further object is to provide a lost motion varying device for a spiral groove engaging element of the rotary reciprocating plunger of the pump.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a variable stroke plunger pump incorporating the features of this invention.

FIG. 2 is a sectional view on the line 22 in FIG. 1.

FIG. 3 is a sectional view on the line 3-3 of FIG. 1.

FIG. 4 is an enlarged side elevation of the angularly moving adjusting element shown in FIG. 1.

FIG. 5 is an end elevation of the element shown in FIG. 4.

FIG. 6 is a plan view of the adjusting element of FIG. 4.

FIG. 7 is a greatly enlarged fragmentary view showing minimum stroke position of the pump.

DESCRIPTION OF THE PREFERRED EMBODIMENT As an example of a preferred embodiment there is shown a pump having a pump body 10 having a bore 11 in which is rotatably and reciprocatably carried the pump plunger 12. Longitudinally spaced intake port 13 and exhaust port 14 are formed in the body 10 cooperating with passageways 15 and 16 formed in the plunger 12. Passageway 15 is in communication with the longitudinal passageway 17 opening at 18 at the head of the plunger 12 while passageway 16 is in communication with the longitudinal passageway 19 opening at 20 to communicate with the cylinder bore chamber 21 formed by the bore 11 and cylinder head 22.

The plunger is rotated by a suitable motor having a shaft 23 mounted suitably on the body 10. The motor shaft 23 is provided with an axially slidable driver tongue 24 which extends into the transverse slot 25 formed in the plunger 12 so that the plunger 12 is free to axially reciprocate as it is rotated by the motor shaft 23.

Axial reciprocation of the plunger 12 is accomplished during the rotation of the plunger by a spiral groove 26 formed in the periphery 27 of the plunger which is engaged by the stroke control ball 28 which is carried in a retaining socket 29 of the stroke control slide 42 reciprocatable in the angularly disposed guide slot 30 formed in the body 10 which merges with the bore 11. The ball 28 has lost motion travel relative to the groove 26. The lower surface of the spiral groove 26 has the same slope as the guide slot 30 in the body 10. Thus the ball 28 moves from contact point 32 with the spiral groove 26 for maximum plunger travel to contact point 33 for minimum plunger travel, so as to effect a variable plunger travel or stroke adjustment indicated at 34, with the ball always maintaining contact with the surface 31 of the plunger in any adjusted position. An eccentrically positioned stroke control crank pin 35 is formed on the lower end .of the stroke control rockshaft 36 journaled in a suitable bore 37 formed in the body 10 to be rocked by its control handle 38 to swing about a main axis 39. A set screw 40 threadedly mounted in the body 10 and extending into the annular groove 41 serves to demountably secure the rockshaft 36 in adjusted operative position, the crankpin 35 operating in the elongated slot 43 formed in the stroke control slide 42.

It will be noted that by swinging the rockshaft 36 by handle 38 to desired adjusted positions, the distance 34, FIG. 7, may be varied so as to regulate the amount of travel of the plunger 12 relative to the normal fixed lead travel effected by the lead of the spiral groove 26.

While the apparatus herein disclosed and described constitutes a preferred form of the invention, it is also to be understood that the apparatus is capable of mechanical alteration without departing from the spirit of the invention and that such mechanical arrangement and commercial adaptation as fall within the scope of the appendent claim are intended to be included herein.

'1 claim:

1. A variable stroke plunger pump comprising in combination:

(A) a pump body having a cylinder bore,

(B) a pump plunger rotatably and axially reciprocatably carried in the cylinder bore,

(C) a cylinder head fixed to the body over an end of the cylinder bore to form a cylinder bore chamber with one end of the plunger,

(D) a drive motor connected to rotate the pump plunger,

(E) intake and exhaust ports connected to the cylinder bore chamber,

(F) a spiral annular groove formed in the periphery of the plunger having a sloping surface facing away from the cylinder bore chamber end of the plunger,

(G) a stroke control slide mounted on the pump body to move relative to and from the pump plunger in a path of travel parallel to the sloping surface of the spiral annular groove,

(H) and a contact surface on the stroke control slide arranged to engage the sloping surface of the spiral annular groove at various positions to vary the axial 3 4 travel of the plunger and thereby the capacity of the FOREIGN PATENTS cylinder bore chamber and the delivery of the pump. 392,359 9/1908 Franc References Cited UNITED STATES PATENTS 0 2,905,098 9/1959 Monelli 103-157 US. Cl. X.R. 3,120,811 2/1964 Iemison et a1 103157 103157 3,230,892 1/1966 Burns 103I57 HENRY F. RADUAZO, Primary Examiner 

